Wet firewood

[chipsfly09]

Is there a relatively simple formula to get a ballpark figure on the amount of BTUs lost when burning wood as it relates to moistue content.  I assume there is a known btu/lb of firewood at a known moisture content-- say 15percent-  or whatever is conidered "cured" If that number goes up or down-- what effect does that have on btu output.   e.g. if 15 percent went to 30percent-- how much less heat can one expect in terms of heat output.  I hope the question is not too confusing--- Thanks

[bandmiller2]

Chips,I'am sure their is, most of us burn green when we run out of dry.Green wood mixed with dry sometimes helps regulate the fire .My outside furnace burns so hot it dosen't really make much differance,green ,ice ,snow . I quit burning pallets too dry burned too hot unless mixed with green.I think you loose somewhere around 20% evaperating water.Frank C.

[chipsfly09]

Thanks bandmiller--

That is sort of what I have experienced-- My dad and I were having he discussion about how much effort and covered storage space one should devote to wood- he does not have an outdoor furnace like I have-- that will burn just about anything when it gets going-- he relies on more of a woodstove set up--

[RSteiner]

If I remember right it takes 1 BTU to raise 1 pound of water 1 degree.  That said if 10 pounds of wood is 20% moisture versus 30% moisture the weight of the water can be figured and the resulting BTU's necessary to consume it.

Some where I saw the BTU potential of 1 pound of wood at a particular moisture content.  Each type of wood has a different density and specific gravity which is where you more BTU's out of a piece of hardwood which is the same size as a piece of softwood.

The bottom line is the lower the moisture content the more heat you will get.

Randy